1. Field of the Invention
The present invention relates to a controller, for example, a stick lever or a volume control, capable of adjusting the operation amount of an electronic device through the movement of a control member by an operator. Particularly, the present invention relates to a controller that can provide a specific click feeling at a specific position, for example, the center position, within a predetermined operation range of the controller, as well as a control click feeling within the entire operation range of the controller.
2. Description of the Prior Art
In the transmitter used for model radio control devices, a controller or maneuvering device is installed that sets and adjusts various operation amounts of an object to be manipulated, such as a model airplane. For example, the controller installed to the radio control transmitter that manipulates a model airplane includes a joy stick lever for operating various channels for throttle, aileron, elevator and ladder, a trim for fine adjusting each channel, a side lever for adjusting the number of revolutions of an engine and a pitch angle of a propeller, and volume controls. An operator or manipulator operates the controller with his fingertips to set and adjust various control amounts for controlling an object to be manipulated.
Some controllers include a click generation means that produces a click feeling to a fingertip of the operator which represents a physical indication of an operation amount of the controller by the fingertip. The click feeling means a delicate mechanical resistance transmitted to the controller in response to an operation of the controller, or a delicate mechanical resistance transmitted to the controller which is produced by snapping a catch or pawl into a position when the controller is operated, or a feeling similar to the feeling felt by an operator due to the mechanical resistance. For example, the click feeling is a physical reference for recognizing either how much a controller, such as a volume control, is rotated or the specific position within the operation range of the controller.
In order to control a model airplane with a radio control transmitter, the operator normally operates the transmitter at hand with only fingertip feeling, while watching an object to be manipulated. In this mode of the operation, it is considered that the click generation mechanism for producing the click feeling is an important factor for the controller in the radio control transmitter. A notch array, for example, is known as a typical click generation means. The notch array includes a serration formed in the movable range of the controller along an operation direction for which a pawl can be engaged. The serration means a mechanical structure in which a large number of sawlike teeth or notches is formed continuously and alternately in the operation direction along the edge. The Japanese patent publication No. 2006-102011 discloses a radio control transmitter which includes a side lever having a notch array acting as a click generation means.
Furthermore, in the operation range of the controller for the radio control transmitter, it is preferable to obtain a specific click feeling at a specific position within an operation range to recognize the current setting position of the controller. For example, in the controller having a predetermined operation range adjustable in both divergent directions from the neutral point, it is convenient for the manipulation of the controller to know the neutral point by feel during the operation. Thus, a click generation means that produces the specific click feeling, namely center click feel, when the controller comes to the central position of the operation range is preferably provided in the controller.
More specifically, in the notch array including the serration and the pawl, a notch deeper than other notches, which is one of the notches of the serration, is formed at the center of the serration region which is formed continuously over the operation range of the controller. The pawl is formed of a metal spring and is moved so as to engage with the notches one by one including the deep notch.
According to the notch array explained hereinabove, the click feeling can be obtained continuously over the operation range of the controller due to the notch array formed in the serration and the pawl made of metal-spring. At the center of the operation range, the pawl snapping into the deep notch allows a stronger click feeling so that the center position of the operation range can be sensed physically.
However, there are several drawbacks in the conventional controller which is provided with the deep notch for producing the center click feeling which is disposed at the specific point over the operation range of the controller, such as the center of the continuous serration. Firstly, if the bottom angle of the notch in the serration or the peak angle of the tooth in the serration is fixed, and the notch which is deeper than other notches is formed at a specific point of the serration, the pitch between notches or teeth of the serration is widened. In other words, the gap between teeth of the serration of the deep notch at the specific point becomes larger than the gaps of the other serration. The notch and tooth pitch forming the serration at the specific point is different from those at other portions. The uneven pitch leads to varying the variation amount per pitch between the region including the specific point and other portions during operation, and thus the maneuvering feeling of the controller becomes less appealing. If the notch and tooth pitch of the serration including the specific point is constant, it is impossible to form the deeper notch at the specific point of the serration so long as the bottom angle or the peak angle of the serration is fixed.
In the controller with the conventional click generation means, the serration is molded with a resin material, and a pawl made of a metal spring is engaged with the serration so that a predetermined click feeling is obtained. However, it is not necessarily technically easy from the manufacturing stand point to use two kinds of materials including resin and metal and to machine and assemble them to produce the predetermined click feeling. As a result, the production costs increase. For this reason, it is convenient to manufacture the whole of the click generation means with resin only, if possible. However, it is difficult to employ the pawl made of a resin in the click generation means, because the variation amount of a resin, or the spring or resilient property of a resin is small as compared with metal. Furthermore, it is impossible to increase the difference between the notch depth at the specific point and the notch depths in other portions of the serration so that the different click feeling between the specific point and other points may be obtained. Moreover, the resin tends to change its elastic force due to changes in temperature and easy to plastic deform. Thus, the resin is difficult to provide the specific click feeling at the specific position. Generally, the pawl made of the resin cannot provide a sufficient deformation stroke in the deep notch at the specific position of the serration due to plastic deformation, and the specific click feeling cannot be obtained at the specific position.